INCLUSIONS OF POTASSIC PHASES, COESITE AND OMPHACITE IN A COATED DIAMOND CRYSTAL FROM THE MIR PIPE

Abstract

The authors report a continuation of the study of zonally distributed inclusions in an octahedral diamond crystal with a yellow coating in which two syngenetic sanidine inclusions had previously been found. The fact that only one of them was consistent with the stoichiometric formula for sanidine, as well as the abundance of inclusions present in the interior of plane-parallel slice cut out of the central part of the crystal in the (110) plane, prompted the preparation of additional polished sections and further investigations. They found 20 surface microinclusions of potassic phases, 6 of omphacite and 8 of coesite. The chemical and phase composition of the inclusions was studied with a Camebax-Micro probe and a molecular analyzer (Mole and Ramanor U-1000 Raman spectrometers).